Gulf of Mexico Land Cover Change Chronicled in New NOAA Report

A new NOAA report says 13 percent of the U.S. Gulf of Mexico region saw changes to its land cover--paved surfaces, trees, forests, grasses, and wetlands--1996 to 2010. That figure represents 26,516 square miles, almost the equivalent of half the state of Louisiana.

Land cover data records the physical land type, rather than how land is used.

The region added more than 1,536 square miles of development, the equivalent of one football field every 10 minutes.

The counties surrounding Houston, Texas; Orlando and Fort Myers, Florida; and McAllen, Texas (along the Mexican border), are all areas of high increasing growth.

The region lost 1,794 square miles of wetlands over 15 years, and 798 square miles of wetlands were gained, representing a net loss of 996 square miles of wetlands present in 1996. Wetlands lost were largely due to water and development. Coastal areas in Louisiana, western Alabama, the Orlando–Tampa corridor and Fort Myers in Florida, were all areas with noted losses.

The Gulf of Mexico experienced a net loss of 8,706 square miles of forest cover (13,225 square miles of forests changed to other types of land cover while 4,519 square miles of forest were regrown). Most of these changes occurred in areas dominated by upland forest types, away from the immediate coast and the largest urban centers.

The Gulf of Mexico Regional Land Cover Change Report provides information about the data sets that cover all the coastal portions of Texas, Louisiana, Mississippi, Alabama, the Gulf shore of Florida, and a portion of southwestern Georgia that drain away from the Atlantic Coast. The report is based on land cover change data from the NOAA Coastal Change Analysis Program (C-CAP). Land cover data are obtained and analyzed approximately every five years using satellite-based image data.

“People know the region is changing, but it is hard to pinpoint the extent. This report provides an overview of that information with numbers, graphics, and maps,” said Nate Herold, C-CAP coordinator at the NOAA Office for Coastal Management. “Communities can use this information to see how previous land use decisions and changes in climate affect land cover, and help make informed decisions about the future.”

The Gulf regional study is part of a new group of NOAA nationwide reports showing that between 1996 and 2010, 64,967 square miles in coastal regions -- an area the size of Florida -- experienced changes in land cover, including a decline in wetlands and forest cover, with development a major contributing factor. Over the past five years, NOAA scientists analyzed land cover data, which records the physical land type, rather than how land is used.

Overall, 8.4 percent of the nation’s ocean and Great Lakes coastal regions experienced these changes. The five regional reports provide information about the data sets that cover the nation’s ocean and Great Lakes coastal regions: West Coast, Gulf of Mexico, Great Lakes, Northeast, and Southeast. The reports identify a wide variety of land cover changes that can increase a community’s vulnerability to impacts from climate change, such as loss of coastal barriers to sea level rise and storm surge.

Herold said private industry, government, and nonprofits also use land cover data and maps to make decisions about the future. For example, coastal land cover data helped the Ocean Conservancy develop an atlas to inform ecosystem restoration planning in the Gulf of Mexico. The Mississippi-Alabama Habitat Mapper created by NOAA’s Office for Coastal Management was used to identify high-priority habitats, including those impacted by the BP Deepwater Horizon oil spill.